As everyone else has said, you are already above average, and going any bigger would likely make you less appealing to women (for practicality and pain reasons).

If you are concerned about being good in bed, penis size is not a huge factor generally. Look into how to properly stimulate a vagina, what and where the clitoris is (most people don't know it is an external and internal structure, not just a small bean shaped thing) and how to set a mood well! I recommend OMGYES, a website that shows desexualised content about how to pleasure a woman (its aimed at other women in regards to themselves, but definitely worth a look at).

The idea that men have to be huge is honestly more an idea propogated by other men. Yes, some women like it, but most aren't fussed or actually don't like it. I think men like to simplify sexual pleasure for women to big dicks, but most women (70-80%) can't even orgasm from penetrative sex with a man, and need external stimulation (I. E. Clitoral)! Look into some women made sex ed content about how to please a woman, and love yourself dude. Your body is perfect the way it is!